Biological performances of Ni-Cr porcelain alloy are highly correlated with released metallic ions. Released metal ions from Ni-Cr porcelain alloy, particularly Ni, Be can induce inflammation of the adjacent periodontal tissue and oral mucosa. In vitro evidence has indicated that the immune response can be altered by various metal ions. Allergic reactions due to metallic dental restorations have been documented. Ni has especially been identified as being highly allergenic. The cytotoxicity and corrosion level of Ni-Cr porcelain alloy is increased after recasting. The Ni-Cr porcelain alloy produced according to technology requirements has good biological safety. Ni-Cr porcelain alloy released a few of metal ions which might induce allergy and density of adjacent periodontal tissues, for the stimulation effect of these metal ions. There is no evidence to suggest that Ni-Cr porcelain alloy restorations has systemic toxicity or carcinogenic/genotoxic effect to human.

BACKGROUND:Previous studies show that the fracture resistant force of endodonticaly treated teeth can be improved by post. But this idea has been controversial in recent years. Many scholars believe that the root canal preparation might weaken dental root the post increases the risk of tooth fracture. OBJECTIVE: To evaluate the fracture resistance ability of severe wedge-shaped-defect premolar to oblique loading, which was restored with fiber reinforced composite posts by different therapy methods. METHODS:A total of 50 human maxilary premolars were randomly divided into five groups, with ten teeth in each group. They were given folowing treatments: Group A: 10 untreated premolars; Rest 40 premolars of Groups B, C, D and E were prepared 1/3 bucco-lingual distance for artificial severe wedge-shaped defects at the buccal cervix. Group B: untreated severe wedge-shaped defects premolars; Group C: severe wedge-shaped defects premolars were endodonticaly treated, remaining dentin over hang above the wedge shaped defect, LuxaPost posts reinforced in buccal canal and lingual canal, LuxaCore composite resin restored dentin defect; Group D: severe wedge-shaped defects premolars were endodonticaly treated, LuxaPost posts reinforced in buccal canal and lingual canal, LuxaCore composite resin restored dentin defect, and then covered with ful metal crown; Group E: severe wedge-shaped defects premolars were endodonticaly treated, removing dentin over hang above the wedge shaped defect, LuxaPost posts reinforced in buccal canal and lingual canal, restored with LuxaCore composite resin, and then covered with ful metal crown. Fracture resistance of each specimen was measured in each group. RESULTS AND CONCLUSION: The fracture strength of each group were Group A (1 002.69±147.62) N, Group B (439.28±66.34) N, Group C (958.30±101.23) N, Group D (1 207.09±143.48) N, and Group E (1 056.44±139.30) N. Group D had the highest fracture strength (P < 0.01), while Group B had the lowest fracture strength (P < 0.01). There were no significant difference among the fracture strength of Group A, Group C and Group E. Our findings indicated that the fracture resistance of the severe wedge-shaped defected premolar can be improved by fiber reinforced composite post and dentin above wedge shaped defect remained.

BACKGROUND:Someone regards that treatments such as root canal therapy and post-core restoration can increase the fracture probability of teeth. Can fiber reinforced composite post enhance the fracture resistance of the severe wedge-shaped defected premolar? Three-dimensional finite element can simplify complex dental systems into a model analyzed by computer, and conduct biomechanical research through the model analysis. OBJECTIVE:To analyze the stress distribution of sever wedge-shaped defected first premolar which restored by fiber reinforced composite post and composite resin. METHODS:We established the three-dimensional finite element models of severe wedge-shaped defected maxil ary first premolar before and after restoration with fiber reinforced composite post and composite resin. The maximum bite force was designed to 267 N that was applied at 45° angle. Then, we analyzed the distribution of maximum principal stress in finite element models. RESULTS AND CONCLUSION:The maximum principal stress was concentrated in the tip of defected region. After restoration, the distribution of maximum principal stress was similar to that of the normal premolar, and the tensile stress was distributed uniformly in the upper-central part of buccal root. It may be beneficial for improving fracture resistance ability of severe wedge-shaped-defect premolar by restoration with fiber reinforced composite post and composite resin.

Objective To investigate the clinical features and disease-causing mutations of familial hypomagnesaemia with hypercalciuria and nephrocalcinosis.Methods In February 2016,a 24 year old female patient with left kidney stone and nephrocalcinosis in bilateral kidneys was admitted to our hospital.One month prior to this admission,she had been treated by PCNL to remove the most part of left kidney stone in otherhospital.Mter admission,She was found hypomagnesaemia (serum magnesium 0.65 mmol/ L) and hypercalciuria (24h urine calcium 364.0 mg) but with normal renal function (serum creatinine 101.5μmol/L).And the remained part of left kidney stone was removed by flexible ureteroscope.As she was considered probably with an autosomal recessive FHHNC,an analysis of CLDN16 and CLDN19 gene mutations was performed using her and her parents'peripheral white blood cells.Results Mutation analysis revealed this patient had two heterozygous mutations in the CLDN16.One is an one-base deletion mutation in the 123th codon in exon 2:368delA.The other is a missense mutation in the 139th codon in exon 2:416C →T which resulted in an amino acid change Ala139Val.Her parents respectively had one of each heterozygous mutation.In the six months follow-up,an oral administration with hvdrochlorothiazide,potassium citrate,and calcium magesium supplements significantly reduced her hypomagnesaemia (serum magnesiun 1.0 mmol/L) and hypercalciuria (24-h urine calcium 156.0 mg),and no stone recurrence and aggravation of nephrocalcinosis and renal dysfunction occurred.Conclusions We diagnosed a patient with FHHNC who had a novel compound heterozygous mutation of CLDN16.This rare disease should be suspected if there are three constant clinical features of hypomagnesaemia,hypercalciuria and nephrocalcinosis,and verified with CLDN16 and CLDN19 gene test.Currently the option for treatment of FHHNC is symptomatic treatment until severe deterioration of renal function.The hydrochlorothiazide,potassium citrate,and calcium magesium supplements may have considerable effects on hypomagnesaemia and hypercalciuria.

Objective To evaluate the feasibility and clinical efficacy of intra-abdominal exposure instruments in laparoendoscopic single-port nephrectomy(LESS-N).Method From February 2012 to July 2016,61 cases of LESS-N were performed in our center.There were 34 males and 27 females with a mean age of (60.3 ± 9.4) years old (ranging 36-72 years old).There were thirty-nine cases of renal tumors and twenty two cases of nonfunctioning kidney.The patients were divided into two groups.Group A included 39 cases that underwent conventional LESS-N (22 radical nephrectomy/17 simple nephrectomy).Group B included 22 cases that underwent intra-abdominal exposure instruments assisted LESS-N (17 radical nephrectomy/5 simple nephrectomy).The perioperative and postoperative data were collected and analyzed retrospectively.Results All the procedures of these two groups were completed successfully.In Group A,four patients were added one 5 cm additional trocar and two patients were converted to open surgery.No additional trocars or conversion to open surgery were needed in Group B.For LESS radical nephrectomy,there were no significant differences of mean tumor diameter (5.7cm vs.5.4 cm,P =0.65) between two groups.The average operative time was (95.1 ± 43.9) min in Group B which was lower than that in Group A (127.4 ± 61.9) min (P ＜ 0.01).The mean renal vascular processing time was declined from (25.4 ± 10.1)rmin in Group A to (18.8 ± 8.9)min in Group B (P ＜ 0.05).The mean estimated blood loss was (128.6 ± 51.1) ml in Group A and (98.7 ±-57.6) ml in Group B (P ＜ 0.05).No severe intraoperative and postoperative complications occurred in both group.Conclusions Intra-abdominal exposure instruments are feasible and effective for LESS-N.This system may shorten the operation time,reduce the amount of bleeding and improve surgical accuracy.

Objective:To investigate the feasibility and safety of laparoendoscopic single-site combined with transurethral approach for unilateral retrograde nephroureterectomy in the treatment of upper urinary tract epithelial carcinoma.Methods:The clinical data of 12 patients from January 2018 to November 2019 with unilateral retrograde nephroureterectomy were analyzed retrospectively. There were 7 males and 5 females with an average age of 65.9 years, the age ranged from 50 to 78 years.There were 8 cases with left ureteral tumor, 6 cases with left renal pelvis tumor, 4 cases with right tumor(2 cases of right ureteral tumor and 2 cases of right renal pelvis tumor). Surgical methods: 1470 laser sleeve was used to remove the inner segment of the ureter bladder wall after the lower ureter was clipped through abdominal approach, and the urethra was inserted under the guidance of zebra guide wire.The operation time, intraoperative blood loss, intraoperative auxiliary cannula, postoperative hospital stay, postoperative drainage tube removal time, intraoperative and postoperative complications, postoperative pathology were recorded.Results:All of the operations were successful. The mean operation time was 194(135-260)min, the mean estimated blood loss was 50(25-100) ml, and the mean hospitalization time was 11.6(5-24)d. Among the 12 patients, 8 patients had abdominal drainage tube after operation. The mean time for drainage was 6.8(3-11)d. One patient added a 5 mm ancillary port.One patient had urinary leakage at the bladder anastomotic site, the catheter was removed 3 weeks later. The other patients had no postoperative incision infection, fever, bleeding, venous thrombosis and other related complications.No patient received blood transfusion and the pathological margin was negative. The median follow-up time was 12 months (5-15 months). One patient died of lumbar metastasis 8 months after operation, and others were neither tumor recurrence nor distant metastasis.Conclusions:The application of laparoendoscopic single-site combined with transurethral approach for unilateral retrograde nephroureterectomy in the treatment of upper urinary tract epithelial carcinoma is safe, accurate and effective, with less trauma and less bleeding. It is worth applying in clinical practice.